Hepatoprotective triterpene saponins from the roots of Glycyrrhiza inflata.

Two novel oleanane-type triterpene saponins, licorice-saponin P2 (1) and licorice-saponin Q2 (3), together with nine known compounds 2, 4-11, have been isolated from the water extract of the roots of Glycyrrhiza inflata. The structures of these compounds were elucidated on the basis of spectroscopic analysis, including 2D-NMR experiments (1H-1H COSY, HSQC, HMBC and ROESY). In in vitro assays, compounds 2-4, 6 and 11 showed significant hepatoprotective activities by lowering the ALT and AST levels in primary rat hepatocytes injured by D-galactosamine (D-GalN). In addition, compounds 2-4, 6, 7 and 11 were found to inhibit the activity of PLA2 with IC50 values of 6.9 µM, 3.6 µM, 16.9 µM, 27.1 µM, 32.2 µM and 9.3 µM, respectively, which might be involved in the regulation of the hepatoprotective activities observed.

Bioactive constituents of oleanane-type triterpene saponins from the roots of Glycyrrhiza glabra.

Three new oleanane-type triterpene saponins, namely licorice-saponin M3 (1), licorice-saponin N4 (2), and licorice-saponin O4 (3), an artificial product (4), as well as five known triterpene glucuronides (5-9), were isolated from the roots of Glycyrrhiza glabra L. Their structures were established using 1D and 2D NMR spectroscopy, mass spectrometry, and by comparison with spectroscopic data reported in the literature. The inhibitory effects of the selected compounds on neuraminidase were evaluated, and the preliminary structure-activity relationship was also predicted.

A green and efficient protocol for large-scale production of glycyrrhizic acid from licorice roots by combination of polyamide and macroporous resin adsorbent chromatography.

A green and efficient method for large-scale preparation of glycyrrhizic acid from licorice roots was developed by combination of polyamide and macroporous resin. The entire preparation procedure consisted of two simple separation steps. The first step is to use polyamide resin to remove licorice flavoniods from the licorice crude extract. Subsequently, various macroporous resins were tried to purify glycyrrhizic acid, and HPD-400 showed the most suitable adsorption and desorption properties. Under the optimized conditions, a large-scale preparation of glycyrrhizic acid from licorice roots was carried out. A 20 kg raw material produced 0.43 kg of glycyrrhizic acid using green aqueous ethanol as the solvent. The purity of glycyrrhizic acid was increased from 11.40 to 88.95% with a recovery of 76.53%. The proposed method may be also extended to produce large-scale other triterpenoid saponins from herbal materials.

[Multi-index determination and optimization of liquirtin separated from polyamide resin].

To optimize the separation process of liquirtin from glycyrrhiz by static, dynamic adsorption and desorption experiments on polyamide resin, with liquirtin, isoliquiritin and glycyrrhizic acid as the study index. The optimum process conditions were that the pH of solution was regulated to be 7.0, the concentration of liquirtin was 1.296 g x L(-1), the volume of loading buffer was 3 BV. After absorption, efforts shall be made to elute resin with water, 10%, 20%, 30% ethanol (3 BV for each), collect 20% ethanol eluted fraction, and recover solvents. The results showed lower contents of such impurities as isoliquiritin and isoliquiritin in extracts sepaprated under this process conditions, as well as an increase in purity of liquirtin from 4.86% to 88.5%. The method was simple and feasible, it could obtain a higher purity in extracts from liquirtin and provide basis for industrialized separation and preparation of liquirtin.